<template>
  <el-breadcrumb class="app-breadcrumb" separator="/">
    <transition-group name="breadcrumb">
      <el-breadcrumb-item v-for="(item, index) in levelList" :key="item.path">
        <span v-if="item.redirect === 'noRedirect' || index == levelList.length - 1" class="no-redirect">
          {{ item.meta.title }}
        </span>
        <a v-else @click.prevent="handleLink(item)">{{ item.meta.title }}</a>
      </el-breadcrumb-item>
    </transition-group>
  </el-breadcrumb>
</template>

<script setup name="Breadcrumb">
  import usePermissionStore from '@/store/modules/permission'

  const route = useRoute()
  const router = useRouter()
  const permissionStore = usePermissionStore()
  const levelList = ref([])

  function getBreadcrumb() {
    // only show routes with meta.title
    let matched = []
    const pathNum = findPathNum(route.path)
    // multi-level menu
    if (pathNum > 2) {
      const reg = /\/\w+/gi
      const pathList = route.path.match(reg).map((item, index) => {
        if (index !== 0) item = item.slice(1)
        return item
      })
      getMatched(pathList, permissionStore.defaultRoutes, matched)
    } else {
      matched = route.matched.filter(item => item.meta && item.meta.title)
    }
    // 判断是否为首页
    if (!isDashboard(matched[0])) {
      matched = [{ path: '/index', meta: { title: '首页' } }].concat(matched)
    }
    levelList.value = matched.filter(item => item.meta && item.meta.title && item.meta.breadcrumb !== false)
  }
  function findPathNum(str, char = '/') {
    let index = str.indexOf(char)
    let num = 0
    while (index !== -1) {
      num++
      index = str.indexOf(char, index + 1)
    }
    return num
  }
  function getMatched(pathList, routeList, matched) {
    let data = routeList.find(item => item.path == pathList[0] || (item.name += '').toLowerCase() == pathList[0])
    if (data) {
      matched.push(data)
      if (data.children && pathList.length) {
        pathList.shift()
        getMatched(pathList, data.children, matched)
      }
    }
  }
  function isDashboard(route) {
    const name = route && route.name
    if (!name) {
      return false
    }
    return name.trim() === 'Index'
  }
  function handleLink(item) {
    const { redirect, path } = item
    if (redirect) {
      router.push(redirect)
      return
    }
    router.push(path)
  }

  watchEffect(() => {
    // if you go to the redirect page, do not update the breadcrumbs
    if (route.path.startsWith('/redirect/')) {
      return
    }
    getBreadcrumb()
  })
  getBreadcrumb()
</script>

<style lang="scss" scoped>
  .app-breadcrumb.el-breadcrumb {
    display: inline-block;
    font-size: 14px;
    line-height: 50px;
    margin-left: 8px;

    .no-redirect {
      color: #97a8be;
      cursor: text;
    }
  }
</style>
